Various isotopes of actinide elements have been used for many years for the development of radiation detectors, e.g., used in the Lawrence Livermore National Laboratory Radiochemical Diagnostic Tracer Program. For example, americium-241 and curium-244 are extensively used.
The conventional method for fabrication of these isotopes into radiation detectors involves powder mixing techniques. Oxides of actinides such as americium-241 and curium-244 are mixed with aluminum metal powder and the mixture is then pressed into disks under high pressure. Although this technique has been used very successfully for many years at LLNL, there are disadvantageous limitations on the configuration and size of the shapes which can be produced using such powder techniques. Moreover, it is difficult to obtain uniform powder mixtures and dust is generated during the mixing operation.
In view of these disadvantages, the problem exists to provide new alloys for use in radiation detectors, as well as improved methods for their preparation. It has been particularly desired to have such an alloy, including those of americium and curium which can be cast or rolled into a wide range of sizes and shapes. Furthermore, it is particularly desired to have such an alloy which is ductile, homogeneous, easy to prepare and of a fairly high density. Similarly, it is desired to have such alloys for use as sources of the radioactive elements for other purposes.
Toward this end, several different alloy systems have recently been investigated, including: americium/lead, americium/aluminum/ and americium/uranium. However, none of these systems proved suitable. All were brittle, non-homogeneous, difficult to prepare, and/or of insufficient physical and/or chemical properties, e.g., of too low a density.
In addition, various known alloy systems of plutonium are inapplicable to the radiation detectors of the Tracer Program because of the interference of the radioactivity of plutonium with the underlying mechanism of the radiation detection using the actinide, typically transplutonium elements. Thus, such alloy systems and the technology related thereto are inapplicable, as are various other alloys of reactive metals. See, for example, U.S. Pat. Nos. 2,867,530; 2,809,887 and 3,600,586.